A digital transmission system typically encapsulates user traffic into frames with overhead for synchronization, system management and other purposes. When the overhead data is transmitted, user traffic has to be put into a buffer and wait for the next available time slot for transmission. Thus, latency and latency jitter may be introduced. In addition, in some transmission systems such as digital microwave radios, user data typically is transformed in the interface from one transmission form and protocol to another, put into some kind of frames, combined with redundancy for error detection and/or correction, and modulated into a waveform for transmission. Each of these processes introduces delay.
Other sources of latency and latency jitter to user data include line interface data buffering, error correction encoding/decoding, data framing and overhead insertion. When the user data goes through a series of digital transmission systems, this additional latency will not only accumulate, its variance or jitter may also spread into a wider range. For some data transmission applications, minimum latency and latency jitter is critical.
The approaches described in this section are approaches that could be pursued, but not necessarily approaches that have been previously conceived or pursued. Therefore, unless otherwise indicated, it should not be assumed that any of the approaches described in this section qualify as prior art merely by virtue of their inclusion in this section.